Absolute Calibration. III. Sirius & Sun IR spectra

This result is based on a newly derived independent calibration in the visible of similar accuracy to the previous standard one, with which it is combined. We use a large variety of approaches in the infrared to reach about three times smaller error than for previous absolute calibrations.

The results in the two wavelength regimes are in agreement, providing a consistent link from the visible throughout the near- and mid-infrared. The Sirius-based zero-point at 5557.5{AA} (in vacuum) is 13.436{+/-}0.081x10^-12^W/cm^2^/{mu}m, based on the improved value for Vega of 3.473{+/-}0.018x10^-12^W/cm^2^/{mu}m and the measured magnitude difference between the two stars. At 2.1603{mu}m, the zero-point is 4.225{+/-}0.025x10^-14^W/cm^2^/{mu}m taking Sirius at a magnitude of -1.395.